not too bad.. i have the 3.4 in my auto taco at 137k miles and used M1 from 52k miles to 85k miles or so then switched to Valvoline synpower up until my last oil change at 136k miles. i now run PP and for all of the above oil changes i changed it from 6500 - 7500 miles pending my driving style during that time period.
i am glad to see PP does well in the 3.4's..